The backbench Labour MP does not wish to be named. He is nursing a majority around the 5,000 mark. His seat is in the South-east of England. It was won from the Tories at the last election. Two weeks ago he was confident of keeping his job and his £45,000-a-year salary. Now he's not so sure.

Last week, as suddenly as the fuel crisis developed from small-scale blockades to full-blown national disaster, the nightmare scenario for the Labour Government emerged. Four opinion polls have suggested that the Conservatives could win the coming general election. Like so much spring snow, Tony Blair's 'impregnable' poll lead has evaporated from the political landscape. His personal ratings are down. He is blamed for the fact that the country almost ground to a halt two weeks ago. The Dome, pensions and a book by The Observer 's chief political commentator, Andrew Rawnsley, have come together to give this Government a bloody nose, cracked ribs and a black eye.

Clare Short said last week that the Dome was 'a disaster'. Truckers said that Gordon Brown had to deliver on fuel tax cuts, or else. Barbara Castle said that it was time for action on pensions. And Rawnsley said the Chancellor had lied about the £1 million party donation from Formula 1 racing millionaire Bernie Ecclestone. Blair himself, Rawnsley said, had slipped into mendacity. The Prime Minister has been silent. Now, this weekend, it is fight-back time.

The next five days are vital for this Government. At their annual conference in Brighton, starting today, every one of the big Labour hitters will have their chance to reinvigorate support for the Government. They have been rattled. Suddenly the Tories are not such a laughing stock as before.

'Whatever we say in public, of course we take notice of the opinion polls,' one Cabinet Minister said on Friday. 'There were those saying we had the next election in the bag. But I always thought the polls were underestimating the Tories' support. At least we now know where we stand. At least now we can concentrate political minds. The Tories can win.'

For the backbencher, such a scenario was always possible. 'When you have a small majority, you know that you can lose, whatever the polls are saying,' he said. 'We had been lulled into a false sense of security.'

Tony Blair's speech is on Tuesday. Senior Downing Street advisers say that he is going to map out 'the vision thing', something to throw the debate forward, to take this crisis-ridden Government away from the Dome and the fuel revolt and pensions, and set forth a new agenda - the improvement of schools, the health service, crime - on what this Government can do for you. It is critical.

'We have to keep our nerve,' said John Prescott, Deputy Prime Minister and the man charged with ending the conference on a high with a tub-thumping 'trust us' speech on Thursday.

'We need to be fully aware of what this Labour Government's done in carrying out its manifesto. [We need to] look forward to a second term. What this election is about is our justification to ask for a second term.'

But future political seas look choppy. The Dome will not go away. Next month the National Audit Office report on the Greenwich attraction will be scathing about the financial mess. Many are predicting that Lord Falconer, the Minister in charge, will be forced to fall on his sword.

Pensions will not go away. The conference will vote on the issue on Wednesday, and the Labour leadership is well aware it could be defeated.

This week will also see the Danish referendum on entry to the euro with the No campaign leading in the polls. For the pro-euro Blair, a loss across the North Sea will only strengthen anti-euro campaigners here.

And then there is Geoffrey Robinson, the former Paymaster-General, whose book, The Unconventional Minister , will for the first time detail his side of the £373,000 home loan he gave Peter Mandelson. It has already been bought for serialisation by the Daily Mail . Expect fireworks.

Among all these icebergs, the Government has to keep some semblance of a straight line. Blair is arguing in Downing Street that his administration must not appear to be knocked off course by every passing disaster. They must try and rise above it all, but also appear to be listening and responding. It is a difficult trick to pull off.

Prescott, speaking to The Observer last week, said that now, more than ever, it is imperative for the Government to define the clear dividing lines between Labour and the Conservatives - some tax and some spending versus less tax and, the Government argues, less spending. 'Yes, we have some problems. Everyone can see that we have issues which people are expressing strong concerns about; for example, pensions and fuel. We can show substantial evidence of where we have been listening and our solutions in logic and in application are fair, if you believe that those less well off should have the priority. You have to convince electorates and they have got to feel what you are saying is right.'

He knows that the Government has a message to sell, but somehow it is not getting through. Does the tone have to change? Maybe, Prescott admits, a line also pushed by another member of the Cabinet who spoke to The Observer . What is clear is that you can't go on simply blaming the press.

'It's for the Government to prepare its programme to convince an electorate that it's acting in its interests. If it's able to deliver in a confident way and has a good record of delivery - which this Government has without a doubt - keep your nerve, be proud of what we've done, but get out and tell them.

'I am not a great one for polls, but I have noticed them. We've had unpopular polls - about transport two years ago and we dealt with the problem and we got the economy right and we put a huge amount of investment in and everybody said that's good. We did the same for hospitals and everybody said that's good and the polls tended to show it. We had unpopular polls in the spring and after the comprehensive spending review and the health expenditure and the transport expenditure; in the summer we improved and we showed that we were delivering.' He believes fortunes can change again.

Matthew Taylor, the head of the well connected left-wing think-tank, the Institute of Public Policy Research, says that a little contrition wouldn't go amiss. 'Sometimes you have to eat humble pie,' said Taylor, who was assistant general secretary of the Labour Party before the last general election and was a senior member of the campaigns team. 'There needs to be a line drawn under the recent problems, some excitement needs to be created about new government initiatives. The debate needs to go forward.'

Prescott, like so many politicians, cannot stomach the word 'sorry'. Keep apologising for everything and in the end nobody will trust you, he argues. 'Have you ever heard an editor [of a newspaper] apologise for getting something wrong? Blimey, if you adopted that principle when you got things wrong every paper would have the editor up every day apologising for what he had wrong.' He doesn't want the Government going down the same track.

'Labour will lose the next election if it can't maintain the trust of the people,' he says. 'That will always be so. We must never be complacent, that is something the Prime Minister always says. Never take the electorate for granted.'

Pollsters agree. Professor John Curtice, polling expert at Strathclyde University, says that the reason that the polls swung so swiftly against Blair (from a 20 per cent lead two months ago to a 4 per cent Tory lead last week) is because the Government committed the cardinal sin in the eyes of the people. The fuel crisis and Dome revealed a Government not in control of events.

The last time there has been such a violent swing in the polls was at the time of the Falklands War, when Margaret Thatcher increased Tory support by 10 per cent. She was tough, in control. Blair appears to have vacillated on fuel and has remained silent on the Dome.

But before Conservative Central Office starts hanging out the bunting, a word of caution. A careful reading of the performance of past governments in the opinion polls would offer Blair some comfort - and give William Hague a salutary warning.

The over-riding point is that governments almost invariably gain ground as election day approaches. In the autumn of 1986, as last week, the Opposition held a narrow lead over the Government. Then, as now, a bald Opposition leader lagged in the personal popularity stakes behind a Prime Minister whose habit was to lead from the front. Then, as now, there was much talk of the governing party losing its landslide majority and facing a hung Parliament. And what happened? The following spring, the governing party - the Tories under Thatcher - returned to power with a 100-seat majority.

Nor was that an isolated event. In nine of the past ten full Parliaments, the final six-to-nine months have seen a swing from Opposition to Government. What seems to happen with a fair degree of regularity is that some people who tell pollsters they yearn for a change when no election is imminent decide in the end that the incumbents aren't so awful after all. It even happened in the run-up to the 1997 general election. The Tories' 31 per cent on polling day was terrible enough - but it was significantly higher than their ratings throughout 1995 and 1996.

So if history repeats itself, Labour ought to win an election next spring reasonably comfortably. What, though, if the polls next March show the race too close to call - say, Labour no more than five points ahead? It is at that point that Blair must decide whether to call a May election or wait until the autumn of next year or the following spring. Looking at what happened over the final 12-18 months of past Parliaments, the story is even more dramatic, with often huge Opposition leads either being cut back sharply or being overturned altogether.

The Tories must face the fact that, even after moving into the lead for the first time in eight years, they remain the second most unpopular Opposition at this point in the political cycle in the 60-year history of polling. Only Labour in the autumn of 1982 stood lower . Yet suppose history does not repeat itself. What if the Tories stay narrowly ahead right through to polling day? Blair could still remain Prime Minister, for Britain's election system is now tilted in Labour's favour. If both Labour and Tories win the same number of votes, Labour is likely to have around 80 more MPs. To be sure of having more seats than Labour, the Conservatives need a 7 per cent lead in the popular vote.

There are three main reasons for this:

* Labour-dominated parts of Britain tend to have smaller constituencies than Tory-dominated areas. If constituencies in Wales and Scotland were the same size as in England, they would elect 23 fewer MPs; Labour would lose 19 of them.

* Turnouts in strong Labour areas tend to be lower than in traditional Tory areas. Low turnouts in safe Labour seats drag down the party's national vote share by two-to-three points, but do not cost it any seats.

* In 1997 tactical voting cost the Tories up to 35 seats.

David Miliband, the unassuming but fiercely intelligent young head of Blair's policy unit, said two weeks ago he believed the first term in power had actually been all about proving Labour was a 'serious party of government', establishing its economic competence, airbrushing out the bad memories.

'This Labour Government is establishing a new collective memory about what it means to be a New Labour Government. Gone is the winter of discontent: in its place a national minimum wage.

He also highlighted a key New Labour problem, knee-jerkism, revealed in all its ridiculous glory earlier this year by the Prime Minister's sudden announcement that louts would be marched to cash machines to withdraw £100 to pay on-the-spot fines. Blair wanted to be seen doing something about crime. Two days later the idea was abandoned as unworkable.

Miliband said: 'On every maths A-level paper it says please read the question carefully before you start to answer,' he warned. 'In the Government often the temptation is to rush in to give the policy answers before you really know what the question is.'

Miliband argues that the key lesson he draws from Al Gore's presidential campaign in America is that the Centre-Left can succeed if it fights on the issues. Gore was behind Bush in the polls, started arguing about health and education, and is now ahead.

'The lesson is that substance beats froth,' Miliband said. 'Essentially the Tories made a decision to attack us on a lot of trivial stuff, but when we produced the national plan [for health], the CSR [Comprehensive Spending Review], that won out.'

Labour officials insist that the week's polls do not reveal some catastrophic shift in the social democratic consensus that was built to win the election in 1997. Get back onto policies and away from the horror of events and the government ship will stop listing. But that's the problem with events. Like icebergs, you don't always know how many there are or when the next one may strike.

The icebergs between Blair and victory

EUROPERISK RATING: Medium DIARY DATE: Thursday

Danish euro referendum. Danish No campaign will win if polls are right. This would damage Government's plan for British euro vote in the next Parliament. Blair braced for pasting.

PENSIONS RISK RATING: High DIARY DATE: Wednesday

Conference votes on a flat rate increase, though Gordon Brown wants to target the poorest while Barbara Castle favours restoring the earnings/pensions link.

FUEL CRISIS RISK RATING: High DIARY DATE: mid-November

End of the 60-day limit set by truckers before the blockades begin again. Gordon Brown has been told he must cut fuel duty or face the consequences.

GEOFFREY ROBINSON RISK RATING: High DIARY DATE: mid-October

Publishes book, The Unconventional Minister.Will tell his tale of the £373,000 loan to Peter Mandelson, which cost both Ministers their jobs. Robinson has scores to settle.

THE DOME RISK RATING: Nuclear DIARY DATE: mid-October

National Audit Office report into Dome finances. Lord Falconer, the Minister responsible, is set for criticism over where money went. Many predict his downfall.